Boilers are appliances for feeding hot water to separate rooms in homes and offices after heating water using combustion heat, which is generated when burning fuel in the boilers. The boilers have come into wide use for the purpose of heating houses or feeding hot water in the houses. The boilers are classified into various types according to the sort of heat sources for heating water or fuel used in the boilers. For instance, the boilers are classified into gas boilers using LPG or LNG and oil boilers using burning-oil according to fuel used in the boilers.
In addition, the boilers are classified into normal type boilers and condensing type boilers. The condensing type boiler has been developed so as to reuse energy, which may be wasted in the normal type boiler. The condensing type boiler operates as follows:
Fuel of the boiler includes hydrogen (H2), which reacts with oxygen (O2) when the fuel is burned so that water (H2O) is created while generating heat. Such water is converted into water vapor due to heat contained in water and the water vapor is exhausted to an exterior in the form of an exhaust gas. Accordingly, if the temperature of the water vapor is lowered below 100° C., the water vapor is again converted into water.
When a phase of a material is shifted, latent heat is emitted or absorbed from/into the material. Therefore, latent heat is generated when the water vapor contained in the exhaust gas is liquefied into water. The condensing type boiler includes a latent heat exchanger so as to heat water by using the latent heat. According to the condensing type boiler, sensible heat contained in the exhaust gas and latent heat contained in the water vapor are simultaneously retrieved, thereby improving the thermal efficiency of the boiler up to 95 to 105%. Therefore, it is preferred to widely spread the high-efficiency condensing type boilers in order to reduce energy consumption.
However, in order to apply the condensing scheme to the oil boiler, a latent heat exchanger for retrieving the latent heat from the exhaust gas must be installed in the boiler separately from a main heat exchanger capable of absorbing combustion sensible heat. Differently from the gas boiler, the oil boiler may generate strong acidic condensing water due to sulfuric components contained in oil fuel, so the latent heat generator must be fabricated by using a material having superior endurance against the strong acidic condensing water. For this reason, the condensing type oil boiler must be provided with the main heater exchanger and the latent heat exchanger, which are fabricated by using mutually different materials.
FIG. 1 is a schematic sectional view of a conventional condensing type oil boiler. The conventional condensing type oil boiler includes a main heat exchanger 12 for absorbing sensible heat generated when fuel is burned in the boiler and a latent heat exchanger 16 aligned in parallel to the main heat exchanger 12 while forming a predetermined space therebetween so as to absorb remaining heat and latent heat from an exhaust gas fed to the main heat exchanger 12. The main heat exchanger 12 is provided at a lower portion thereof with a combustion chamber 11, in which fuel is burned by means of a burner 10. In addition, a plurality of funnels 14 are provided in the main heat exchanger 12. The funnels 14 are connected with an upper portion of the combustion chamber 11 so as to convey an exhaust gas generated from the combustion chamber 11. Water reservoirs 13 are provided between an outer peripheral portion of the combustion chamber 11 and the funnels 14 in order to circulate hot water. Sensible heat of the exhaust gas, which is generated when the fuel is burned in the boiler, is applied to hot water being circulated through the water reservoirs 13.
Arrows shown in FIG. 1 represent a flowing direction of the exhaust gas. As shown in FIG. 1, the exhaust gas flowing upwards from the combustion chamber 11 of the main heat exchanger 12 along the funnels 14 is transferred to a noise-absorbing container 15, which connects an upper portion of the main heat exchanger 12 with an upper portion of the latent heat exchanger 16, so that the exhaust gas is introduced into the latent heat exchanger 16. The latent heat exchanger 16 has a cylindrical structure and the upper portion of the latent heat exchanger 16 is communicated with the noise-absorbing container 15. The latent heat exchanger 16 is provided at an inner portion thereof with a plurality of funnels 18, which are communicated with a funnel support 19 provided at a lower portion of the latent heat exchanger 16. In addition, water reservoirs 17 are provided between the funnels 18 so as to store hot water therein. Latent heat of the exhaust gas passing through the latent heat exchanger 16 is transferred to hot water stored in the water reservoirs 17.
Generally, since condensing water, which is generated because water vapor contained in the exhaust gas is liquefied while passing through the latent heat exchanger 16, represents a strong acidic property, the condensing water may cause environmental contamination. For this reason, the funnel support 19 for collecting the condensing water and a neutralization unit 21 for neutralizing the condensing water collected in the funnel support 19 are provided at a lower portion of the funnels 18. One end of the funnel support 19 is communicated with the funnels 18 of the latent heat exchanger 16 and the other end of the funnel support 19 is coupled with a funnel 20 so that the exhaust gas passing through the funnels 18 may be discharged to an exterior through the funnel 20.
However, the conventional condensing type oil boiler having the above structure presents a problem in that the latent heat exchanger for retrieving latent heat from the exhaust gas is installed separately from the main heat exchanger, so separate manufacturing equipment and jigs must be provided for the conventional condensing type oil boiler. That is, in order to manufacture the conventional condensing type oil boiler, a separate assembling line must be provided and additional labor force is supported. In addition, since parts for the condensing type oil boiler cannot be used for the normal type oil boiler, the manufacturing cost may be increased while reducing the productivity.
Furthermore, the conventional condensing type boiler having the above structure presents another problem in that a volume and a weight of the conventional condensing type boiler may increase as compared with those of the normal type oil boiler, which can absorb only sensible heat from the exhaust gas. For this reason, a relatively large space is required for installing the conventional condensing type boiler, while complicating the manufacturing processes for the conventional condensing type boiler.